Preparation And Performance Research Of Magnetic Materials Ferrite MFe_xO_y Composite Photocatalyst

With the increase of population,rapid socio-economic development,and rapid urbanization,China’s water environment pollution problem is becoming increasingly serious.The per capita water resources of the country are only 1/4 of the world’s per capita water resources,and about half of the cities in the country are short of water.However,the deterioration of water quality makes the problem of resource depletion a double whammy.The data survey shows that the pollution rate of sediment in Rivers and Lakes and reservoirs in China has exceeded 80%,and 17 organic pollutants have been detected in the sediment of the Yangtze River.Actively taking effective measures in water pollution prevention and control,effectively preventing water quality pollution,continuously improving water environment management efficiency,and providing people with a safe water environment.The technology of photocatalytic treatment of organic pollutants has gradually become a focus of research by researchers due to its advantages such as low cost,non-toxic,energy-saving,and high efficiency.Photocatalytic technology can not only degrade many structurally stable and difficult to degrade pollutants,but also has wide applications in energy,such as hydrogen production,carbon dioxide reduction,nitrogen fixation,etc.Therefore,it can be said that photocatalytic technology has brought hope to solve environmental and water pollution problems,and its environmental protection field has great potential.If it can be applied on a large scale,it will effectively alleviate the above contradictions.Magnetically separable photocatalysts are a type of photocatalyst with magnetic response characteristics.It not only has good photocatalytic ability,but also is easily separated and recycled under the action of an external magnetic field.Ferrite MFe_xO_yhas good magnetism and low cost,so it is often used as a magnetic material for composite catalysts.However,according to current literature reports,there are not many practical cases of MFe_xO_y materials applied in photocatalytic degradation due to their inherent disadvantage of easy recombination of photo generated electron holes.Therefore,this paper aims to achieve the efficient degradation of organic pollutants by photocatalytic synergistic activation of H₂O₂ under visible light irradiation by introducing new elements and substances to modify ferrite.The main research content of this article is as follows:1.BaFe₁₂O₁₉/Bi OBr nanocomposites were synthesized by hydrothermal calcination.The experimental results show that BaFe₁₂O₁₉ and Bi OBr are successfully combined.Under visible light,the 10%BaFe₁₂O₁₉/Bi OBr nanocomposite exhibits the highest photocatalytic activity,which can degrade 95%MBT in 3 minutes and completely degrade MBT in 15 minutes,which was 1 times higher degradation efficiency than the Bi OBr nanocomposite.At the same time,10%BaFe₁₂O₁₉/Bi OBr composite can also degrade TCH,CIP and Eosin.ESR spectra showed that hydroxyl radical（·OH）,singlet oxygen（¹O₂）,superoxide radical（·O₂^-）and hole（h⁺）played an important role in the photodegradation process.After adjusting the p H value of the solution,the degradation performance of the catalyst changes,indicating that the catalyst has good stability in neutral environment.At the same time,the hysteresis loop shows that the magnetism of the catalyst has not changed,which proves that the composite material still has good magnetism.Therefore,10%BaFe₁₂O₁₉/Bi OBr composite is a promising photocatalyst,which provides a simple and economical method for preparing visible magnetic composite catalyst.2.By regulating the hydrothermal synthesis of magnetic material BaFe₁₂O₁₉ in a strong alkaline solvent,and further high-temperature calcination,hexagonal sheet like nanomaterials were prepared.Then,Fe S₂ was in-situ grown by introducing a sulfur source,resulting in the synthesis of Fe S₂/BaFe₁₂O₁₉ composite material.Research has shown that the Fe S₂/BaFe₁₂O₁₉ composite catalyst exhibits extremely high degradation performance in the process of activating H₂O₂ to remove pesticides.Fe S₂/BaFe₁₂O₁₉has a qualitative leap in the degradation of imidacloprid compared to two monomer materials,monomers have no degradation performance for imidacloprid,while Fe S₂/BaFe₁₂O₁₉ composite catalyst can completely degrade imidacloprid within 30 min under light irradiation.The experiment also explored the effects of catalyst dosage,H₂O₂ concentration,p H value,pollution concentration,and different light sources on the catalytic results during the photocatalytic process.The in-situ growth of Fe S₂ can greatly enhance the degradation performance of composite materials,and after multiple cyclic tests,the degradation effect still reaches 80%,demonstrating the good durability of Fe S₂/BaFe₁₂O₁₉ material.The capture experiment results showed that·OH,¹O₂,and·O₂^-were the main active substances in the degradation process,and the composite material Fe S₂/BaFe₁₂O₁₉ improved the separation efficiency of photo generated carriers.This work provides a simple and economical method for the preparation of optical Fenton magnetic composite catalysts.3.The magnetic material Co Fe₂O₄ was synthesized by adjusting the strong alkaline solvent hydrothermal method,and then Fe S₂ was in-situ grown by introducing a sulfur source to ultimately synthesize Fe S₂/Co Fe₂O₄ composite material.Research has shown that the Fe S₂/Co Fe₂O₄ composite catalyst exhibits extremely high degradation performance in the process of activating H₂O₂ to remove pesticides.Fe S₂/Co Fe₂O₄ has a qualitative leap in the degradation of imidacloprid compared to two monomer materials,and the monomer has no degradation performance for imidacloprid,while Fe S₂/Co Fe₂O₄ composite catalyst can completely degrade imidacloprid within 20 min under light irradiation.The experiment also explored the effects of catalyst dosage,H₂O₂ concentration,p H value,pollution concentration,and different light sources on the catalytic results during the photocatalytic process.By in-situ growth of Fe S₂,the degradation performance of composite materials can be greatly improved,and after multiple cyclic tests,the degradation effect still reaches 70%,demonstrating the good durability of Fe S₂/Co Fe₂O₄ material.The capture experiment results showed that·OH,¹O₂,and·O₂^-were the main active substances in the degradation process,and the composite material Fe S₂/Co Fe₂O₄ improved the separation efficiency of photo generated charge carriers.This work provides a simple and economical method for the preparation of optical Fenton magnetic composite catalysts.